Hilo
Tonight: Showers. Locally heavy rainfall possible. Lows 65 to 73 near the shore to 57 to 62 at 4000 feet. East winds up to 15 mph. Chance of rain near 100 percent.
Monday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 78 to 86 near the shore to around 66 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Monday Night: Mostly cloudy with scattered showers. Lows 63 to 71 near the shore to 54 to 59 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.
Kona
Tonight: Showers early in the evening, then numerous showers late in the evening. Scattered showers after midnight. Locally heavy rainfall possible in the evening. Lows around 76 near the shore to around 56 near 5000 feet. Light winds. Chance of rain near 100 percent.
Monday: Partly sunny. Numerous showers in the afternoon. Highs 83 to 89 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 70 percent.
Monday Night: Mostly cloudy in the evening then becoming mostly clear. Isolated showers. Lows around 75 near the shore to 51 to 56 near 5000 feet. Light winds. Chance of rain 20 percent.
Waimea
Tonight: Windy and showers. Locally heavy rainfall possible. Lows 66 to 74 near the shore to 57 to 65 near 3000 feet. East winds up to 30 mph. Chance of rain near 100 percent.
Monday: Breezy. Mostly cloudy with scattered showers. Highs 64 to 85. East winds up to 20 mph. Chance of rain 50 percent.
Monday Night: Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.
Kohala
Tonight: Windy and showers. Locally heavy rainfall possible. Lows 66 to 74 near the shore to 57 to 65 near 3000 feet. East winds up to 30 mph. Chance of rain near 100 percent.
Monday: Breezy. Mostly cloudy with scattered showers. Highs 64 to 85. East winds up to 20 mph. Chance of rain 50 percent.
Monday Night: Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.
South Big Island
Tonight: Windy. Showers in the evening, then numerous showers after midnight. Locally heavy rainfall possible in the evening. Lows around 75 near the shore to around 56 near 5000 feet. East winds 20 to 30 mph decreasing to up to 30 mph after midnight. Chance of rain near 100 percent.
Monday: Breezy. Partly sunny with scattered showers. Highs around 85 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 50 percent.
Monday Night: Mostly cloudy in the evening then becoming mostly clear. Breezy. Isolated showers. Lows around 74 near the shore to around 54 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.
Puna
Tonight: Showers. Locally heavy rainfall possible. Lows 65 to 73 near the shore to 57 to 62 at 4000 feet. East winds up to 15 mph. Chance of rain near 100 percent.
Monday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 78 to 86 near the shore to around 66 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Monday Night: Mostly cloudy with scattered showers. Lows 63 to 71 near the shore to 54 to 59 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.
Waikoloa
Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then scattered showers after midnight. Locally heavy rainfall possible in the evening. Lows around 77 near the shore to around 59 above 4000 feet. East winds up to 25 mph with gusts to 45 mph. Chance of rain 70 percent.
Monday: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs 84 to 90 near the shore to 66 to 73 above 4000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.
Monday Night: Mostly cloudy in the evening then becoming mostly clear. Isolated showers. Lows around 75 near the shore to around 55 above 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.
Synopsis
Hurricane Hone is bringing heavy rain capable of causing flash flooding to the Big Island and causing strong winds areawide. Wind and heavy rainfall will gradually diminish by late tonight. A typical breezy trade wind pattern returns for Monday.
Discussion
Today and tonight. Afternoon satellite imagery shows the exposed low-level circulation of Hurricane Hone advancing westward away from the islands. The forecast area remains enveloped the system’s broader cyclonic circulation. Given the rich low-level moisture still in place, and PWATs easily in excess of 2″, forcing will be sufficient to generate extensive cloud cover and light to occasionally moderate showers for most areas through tonight. For the Big Island specifically, a trailing band of convergence is supporting shallow convection over windward zones with rain rates around 1-2″ per hour. The high-res guidance has a reasonably good handle on this feature and indicates organized heavy rain potential will persist until around midnight HST tonight before being shut down by the developing mountain breeze. This will bring storm totals in the wettest locales into the 15 to 20″ range. The Flood Watch remains in effect through Monday but may be allowed to expire earlier.
Meanwhile, gradient winds have diminished this afternoon in response to the departing cyclone. The High Wind Warning for Maui County has been transitioned to a Wind Advisory. Likewise, the Tropical Storm Warning for the Big Island has also been transitioned to a Wind Advisory. All wind headlines remain in effect through 6 AM HST Monday morning.
Monday. At press time, GOES derived precipitable water imagery indicates a very sharp moisture gradient nestled within a sfc-to-mid level ridge axis and positioned approximately 150 miles NE of the islands. Across this gradient, PWATs drop from over 2″ to around 0.8″ over a span of about 50 miles. The transition from moist cyclonic flow associated with Hone to typical anticyclonic trades will be marked the arrival of this moisture boundary on Monday. Upon its arrival, dewpoints will fall into the lower to mid 60s, steering flow for trade wind showers will back to easterly, and the inversion will lower and strengthen considerably. Given the background environment of strong winds and developing subsidence, some consideration was given to an extension of the Wind Advisory through Monday. However, the gradient is modeled to diminish rather quickly and, at this time, it appears that the 6 AM HST expiration time is still in good shape. Reference the Fire Weather section for potential fire weather concerns.
Remainder of the forecast period. Moderate to locally breezy trades prevail during the mid-week period as the remnant circulation of TC Gilma approaches the islands from the east. At this time, consensus among the guidance is that developing troughing NW of the islands will cause Gilma to recurve upon approach to the islands potentially leading to a period of warmer weather featuring higher humidity and light winds this weekend. A more southerly track would bring a greater probability of a wet trade wind type of pattern.
Aviation
Hurricane Hone, currently west-southwest of the Big Island, continues to be the main focus for weather into Monday as it moves further westward and away from the state. Clouds and showers on the outer periphery of Hone will maintain MVFR conditions at most TAF sites across the state through tonight, with occasional IFR conditions possible. Winds will remain elevated with sustained 20-30 kts expected (especially across the usual windy suspects) into the evening before gradually weakening overnight. In addition, thunderstorms are still possible over the Big Island through this evening.
AIRMET Sierra for IFR conditions is in effect for visibilities below 3SM and ceilings below 1000 ft for windward portions of the entire island chain. This AIRMET will likely be cancelled for some, if not all of these areas later this evening or overnight.
AIRMET Sierra remains in effect for mountain obscuration for all other areas and will likely be needed through the night.
AIRMET Tango for strong surface winds in excess of 30 kts is in effect across the island chain. This AIRMET will likely be tapered down or even cancelled overnight.
AIRMET Tango remains in effect for moderate low-level turbulence downwind of island terrain and is expected to be needed through tonight.
Aviation interests should pay close attention to the latest forecast from the Central Pacific Hurricane Center, as well as updates to TC SIGMET Whiskey.
Marine
As of the 0000 UTC (200 PM HST) intermediate advisory from the Central Pacific Hurricane Center, Hurricane Hone was located about 200 miles west southwest of Kailua-Kona, moving west northwest at 12 kt. The system is forecast to continue its west northwest trajectory away from the coastal waters over the next 24 hours. Therefore, all Tropical Storm and Hurricane Warnings for the coastal waters have now been cancelled. However, the combination of Hurricane Hone nearby and a strong high far north of the state is resulting in a tight pressure gradient. A Gale Warning is in effect for the Alenuihaha Channel, Maalea Bay, and the Pailolo Channel through tonight. A Small Craft Advisory will remain in effect for all remaining waters through at least Monday to account for both the strong winds and seas in excess of 10 feet.
The Hilo buoy suggests that surf along east facing shores of the Big Island that was generated from Hurricane Hone is now rapidly declining, and therefore, the High Surf Advisory for Big Island’s east facing shores has been cancelled. However, a disorganized short-period east swell driven by strong trades will continue to impact the state. Buoys and observations from east facing shores of the smaller islands support continuing the High Surf Advisory through tonight.
Surf along south and southeast facing shores of the smaller islands will see an increasing trend tonight through early Monday as a result of Hurricane Hone moving south and southwest of the island chain. However, south shore surf is expected to remain below advisory levels.
Surf along north facing shores is expected to remain tiny over the next several days, aside from some wind swell wrap. Additional short-period east shore swell energy generated from Hurricane Gilma is possible during the second half of this week.
Fire weather
Gusty winds will continue into Monday as drier air spreads across the area from the east. There is at least a low potential for fire weather thresholds for thresholds for wind and humidity to be exceeded late Monday morning through the afternoon. Low confidence due to borderline conditions precludes issuance of a Fire Weather Watch or RFW at this time.
HFO Watches/Warnings/Advisories
Wind Advisory until 6 AM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Central Oahu, Waianae Mountains, Lanai Mauka, Kahoolawe, Maui Leeward West, Haleakala Summit, Kohala, Big Island Interior, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Koolau Leeward, Molokai, Lanai Leeward, Lanai South, Maui Central Valley North, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
High Surf Advisory until 6 PM HST this evening for Olomana, Maui Windward West, Kauai East, East Honolulu, Koolau Windward, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, South Haleakala.
Flood Watch through Monday evening for Big Island,
Small Craft Advisory until 5 PM HST Monday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Oahu Windward Waters, Maui County Windward Waters.
Small Craft Advisory until 6 AM HST Monday for Kauai Channel, Oahu Leeward Waters, Kaiwi Channel, Maui County Leeward Waters, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Gale Warning until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel.
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Data Courtesy of NOAA.gov
(Except for the headline, this story has not been edited by PostX News and is published from a syndicated feed.)
